Carburetor and priming device



2 Sheets-Sheet l JNVENToRs.

A TToRNEx Feb. 21,A 1939. w. B. GOODMAN ET A1.

CARBURETOR AND PRIMING DEVICE Filed Dec. 2s, 195s HS n Feb. 2l, 1939. yw4 B, GOODMAN ET'AL 2,148,265

CARBURETOR ND FRIMTNG DEVICE Filed Dec. 23, 1953 E- Sheets-Sheet 2 I/706 /oo /Ol Q/FTW 5 i O 0,; [96

` 04 /ogrz/ To 86 CYLlNDERS IN V EN TORS.

' Q ATTI'ORNEY.' y

Patented Penal, 1939 e y,UNITED STATES PATENT OFFICE CARBURETOR ANDPRIMING DEVICE Willard B. Goodman, Paterson, N. J., and Jeptha MackenzieMiller, South Bend, Ind., assignors to Bendix Aviation Corporation,South Bend, Ind., a. corporation of Delaware Application December 23,1933, Serial No. 703,778

4 Claims.

In many of the larger high-compression inter- Y nal-combustion enginesit is very diicult to secure a mixture in the cylinders that issufficiently rich to support combustion when the engine is cold.

An object of this invention is to provide an apparatus whereby liquidfuel may be injected into the cylinders to facilitate starting of theengine.

A further object is to utilize the conventional acceleration pump of thecarburetor to supply a priming charge directly to the inlet ports of theengine under certain conditions of operation.

A still further object is to provide a priming device of simplifiedconstruction, which may be formed integrally with the body portion ofthe carburetor.

The above and other useful and novel features of this invention willappear more fully from the following detailed description when taken inconnection with the accompanying drawings, in

which:

Figure 1 is an elevation showing the invention applied to anvairplaneengine;

Figure 2 is a section showing the construction of the priming device; .1

Figure 3 illustrates a modified form of the invention;`

Figure 4 is an enlarged sectional view showing the valve used inconnection with the modication a shown in Figure 3;

Figure 5 is a modification similar to Figure 3 embodying Aa differentarrangement;

Figure 6is a section on line 6---6 of Figure 5;

Figure 7 is a section. on line 'I-l of Figure 6v showing the position ofthe valve when discharging to the fuel nozzle of the carburetor;

Figure 8 is a section similar to Figure 'lv show- Figure 11 isan'exploded'view ofthe severall fparts vconstituting thealtitudelmixture control valve.

Referring more particularly to Figure 1, there'v is shown, for thepurpose of illustrating this invention, a carbureting device embodyingthe inventionas used on an airplane engine; A primreservoir 36.

(Cl. D23-187.5)

ing device 58 is associated with the acceleration pump unit 80 of thecarburetor and discharges directly to the cylinders of the enginethrough fuel ducts52 and 56 which are fixed in the intake manifold-54.

Figure 2 shows a carburetor having a body portion I0 forming a maincarbureting passage I2 in which are positioned the usual venturi I4 andfuel discharge nozzle I6. A throttle valve I8 of the butterfly type ismounted on shaft 20, which is journaled in the walls of the maincarbureting passage I2. lFixed to shaft 20 is a double-armed crank 22,one arm of which connects with rod 24, by means of which the throttlevalve I8 is actuated. The other arm of crank 22 connects through link 26to an acceleration lpump which may be of vany desired construction, butwhich in the illustrated embodiment comprises a piston rod 28 and-apiston 30 which is slidable in a cylinder 32. Fuel is admitted tocylinder'32 through a check valve 34 which communicates with fuel Piston30 is slidably mounted on rod 28 and is yieldingly urged downwardly by acompression spring 38, the upper end of which abuts against a washer 40.The pump discharges througlipassage 42 to the fuel nozzle I6, thedischarge passage being controlled by a pressureresponsive outlet valve44 designed to be opened veither by fuel pressure or by flange 46 on therodv 28 contacting with the projecting stem 48 of the valve 44 (seeFigure 10).

In order to adapt'the acceleration pump just v described to be used as apriming pump, a second discharge passage 50 leads from the cylinder 32and connects by a duct 52 and manifold 54 to a plurality of ducts 56leading to the intake manifold of the engine adjacent the respectiveinlet ports of the cylinders. p y

The passage 52 is controlled by a pressureresponsive valve mechanismwhich comprises a shell 58 forming a chamber 60 in which piston 62,having a valve point 64, is yieldingly urged tothe lower extremity ofchamber 160v by spring 66,

which is hrld in chamber 6 0 by a cap screw 68. A vent 10 is located inthe upper `portion of shell 58 to prevent air lock in'chamber `Ill whenpiston 62 slides therein.

To prime and tart the engine the operator will actuate the th ottlelever16, thus operating the acceleration pump by means ofthe above-describedmechanism. A portionof the acceleration fuel will thereupon be ejectedthrough fuel nozzle I6, but due to the factthat passage 42 is restrictedby valve 44,"a larger portion of thel fuel will pass through duct 5II'to chamber I2 where the resulting pressure will force piston 62upwardlyin cylinder 80, compressing spring 66 and opening passage 52 sothat fuel will be forced to the inlet ports of the cylinders.

When the priming operation has been completed, the operator sets thethrottle in the proper position and starts the engine. When the enginestarts, suction will be transmitted through duct 52 which, together withthe force of spring 66, will hold valve point 64 in contact with valveseat 14 and prevent the further flow of fuel through said valve. 1f theacceleration pump is then actuated, it will discharge to the fueldischarge nozzle I6 of the carburetor through check valve 44 and fuelduct 42.

Figure 3 illustrates a modification of an acceleration pump which isactuated by the throttle mechanism through a linkage consisting of roddouble-armed crank |00 and rod |04, the upper portion of which is madeof flexible material such as a flexible cable wound circumferentially bya tight coiled spring, giving an appearance similar to a conventionalBowden conduit.

'I'he acceleration pump 80 discharges to a fuel duct 82 leading to valvemember-84, which is of the type shown in Figure 4. An arm 98, fixed tovalve member-84 in such a manner as to actuate it, is pivotallyconnected with arm 86 by link 88. Arm 86 .is flxed to the shaft 80 of aconventional mixture control mechanism and is actuated by arm 92 and rod93, which is manually operated through suitable control mechanism at theoperators position. Two offset stops 81, formed on the lever 86 areengaged by arm 92 to move valve 84 when rod 93 is actuated. Theoperation of this device is as follows. When it is desired to prime theengine, the operator moves the mixture control rod 93 to lean position,thereby rotating arm 86 in the clockwise direction, and through the link88, rotating arm 98 in a counterclockwise direction 5to move the valve84 to the position shown in dotted lines on Figure 4, thereby openingthe fuel duct 94 and closing oil the fuel duct 96. Duct 94 leads,through connections similar to those shown in Figure 2, to a pluralityof jets in the intake manifold adjacent the inlet prts of the engine.The operator will then open the throttle valve, thereby operating theacceleration pump by means of the connecting mechanism and pumping fuelthrough check valve I I2 and fuel duct 82 to valve 84 where it isdirected through the passage shown in dotted lines on Figure 4 to fuelline 94 leading to the inlet ports of the engine.

When the priming operation has been completed, the operator moves themixture control lever on the instrument board (not shown) to full richposition, thereby rotating arm 86 in the counter-clockwise direction androtating crank 98 in the clockwise direction through link 88, to movethe valve 84 to the position shown in full lines on Figure 4, closingfuel duct 94 and opening fuel duct 96. The acceleration pump 80 willthen discharge to the fuel discharge nozzle 91 through fuel duct 96. A

Figures 5-9 illustrate a valve mechanism riperable in conjunction withthe altitude mixture control mechanism of an aircraft carburetor forselectively opening and closing a plurality of ports v in a fuel lineleading from the acceleration pump.

The valve mechanism comprises a cylinder |20 in which a shaft |24 isrotatably journaled. A tapered barrel valve member |22 is keyed to theshaft |24 by means of pin |30 projecting through the shaft |24 andslidable longitudinally in a slot in valve member |22, which isyieldingly urged against its seat |26 by means of a spring |28. An

annular groove |34 is cut in the valve member |22 for approximatelythree-quarters of the circumference, to permit fuel to enter saidpassage from the acceleration pump discharge duct |36,

and discharge through either of two ports |40 and |42 leading to themain carbureting passage or the cylinders lof the engine;

The altitude mixture control is also operated by the lever |31 throughthe shaft |24 as best shown in Figures 6, 9, and 11. The shaft |24 isprovided with extensions |50 at its inner end arranged to be insertedinto a slot |52 formed in a rotatable portion |54 of a valve, indicatedgenerally by the reference numeral |56, positioned in the inner end ofcylindrical bore |20. The member |54 is also provided with passages |58.Cooperating with the rotatable portion |54 of the valve |56 is anannular member |60 flxedly secured in the bore |20 and which by means ofa bore |66 and a slot |68 permits air to freely flow from a duct |62connected to atmosphere to a duct |64 leading to the fuel or floatchamber of the carburetor when the slot |68 of member |60 is inalignment with the passages |58 of member |54.

When therotatable portion |54 of the valve member |56 is moved to aposition to close the communication with atmosphere, the fuel reservoiris subjected to the variations of fluid pressure existent intheinduction passage of the carburetor. The pressure to which the fuelin the float chamber is subjected is therefore decreased, whereupon lessfuel will be supplied to the induction passage. The pressure in theinduction passage isv dependent, in part, on the barometric pressure ofthe atmosphere -in which the device is operating, and since the quantityof fuel supplied is dependent in part on the pressure in the inductionpassage, the fuel to air yratio of the mixture supplied by thecarburetor is controlled in accordance with variations in barometricpressure. An altitude mixture control is thus effected.

A spring retained in the inner end of shaft |24 maintains the member |54seated upon the fixed member |60 of valve |56. The shaft |24 is alsoformed with an enlarged portion |12 which closely fits the bore to^prevent communication` between the valve |56 and the valve mechanismcontrolling the primingy of the engine.

The operation of this device is as follows. To prime the engine theoperator rotates the shaft |24 by means of arm |31 and other mechanism(not shown), to move the altitude mixture control mechanism to leanposition, thereby moving the valve member |22 to the position shown inFigure 8, to close the duct |40 and open the duct |42. It is thusapparent that when the acceleration pump is actuated by movement of thethrottle lever it will discharge fuel directly to the inlet ports of theengine, thereby producing a rich mixture for starting purposes.

'When the priming operation has been completed, the operator moves thealtitude mixture control to the rich" position, thereby rotating theshaft |24 in the counter-clockwise direction and rotating the valvemember |22 to the position shown in Figure 7, to close the duct |42 andto open the duct |40. The acceleration pump will then discharge to thefuel nozzle of the carburetor. The appropriate throttle valve setting isthen made and the engine started.

With the devices illustrated and described it is possible to pump liquidfuel direct to the engine to obtain a mixture that is sufficiently richto start the engine.

It is expressly understood that the scope of this invention is tol berestricted by nothing appearing herein except the appended claims.

We claim:

1. In an internal combustion engine, a .plurality of cylinders and acarburetor having a manually actuated acceleration pump, a chambercommunicating with the acceleration pump, connecting means between saidchamber and cylinders, and pressure responsive means in said chamberadapted to normally close said connecting means and to interconnect.said acceleration pump and cylinders when a predetermined pressure isestablished in the acceleration pump.

2. In an aircraft engine, an intake manifold, a carburetor having a maincarbureting passage, means including a fuel nozzle for supplying fuel tothe carbureting passage, acceleration means for supplying an increasedquantity of fuel to the carbureting passage under certain conditions ofoperation, connecting means between the acceleration means and' theintake manifold, and

v pressure responsive means controlling the connecting means to supplyfuel directly to the intake manifold from the acceleration means undercertain conditions of operation.

3. In combination with a carburetor including a fuel reservoir, meansforming a main induction passage and a discharge nozzle for amulticylinder internal combustion engine, an altitude mixture controlVmechanism including a shaft and means to subject the fuel reservoir toiiuid pressures existent in the main induction passage, an accelerationpump, a. priming device mounted on said shaft and comprising means toselectively supply fuel from the acceleration pump to the cylinders ofthe engine and to the discharge nozzle, and manually operable means toactuate said shaft to control the priming device and the altitudemixture control mechanism.

4. In combination with an aircraft carburetor, including a fuelreservoir, a throttle, and means forming an induction passage for amulti-cylinder engine, an altitude mixture control mechanism comprisingmanual means to selectively subject the fuel reservoir to variations inuid pressure in the induction passage o r to atmospheric pressure, amanually operable acceleration pump operated in accordance With throttleposition, and a priming device associated with and dependent on theposition of the altitude mixture control mechanism to ydeliver fuel fromthe accelerationpump to the cylinders of the engine or to the inductionpassage of the carburetor.

WILLIARD B. GOODMAN.- -JEPTHA MACKENZIE MILLER.

